Implement bigint shift intrinsics on x64.

runtime/vm/intrinsifier_arm64.cc

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"  // Needed here to get TARGET_ARCH_ARM64.
 #if defined(TARGET_ARCH_ARM64)
 
 #include "vm/intrinsifier.h"
 
 #include "vm/assembler.h"
@@ skipping 671 matching lines @@
   __ andi(R0, R0, Immediate(~kSmiTagMask));  // Remove inverted smi-tag.
   __ ret();
 }
 
 
 void Intrinsifier::Smi_bitLength(Assembler* assembler) {
   // TODO(sra): Implement as word-length - CLZ.
 }
 
 
+void Intrinsifier::Bigint_lsh(Assembler* assembler) {
+  // TODO(regis): Implement.
+}
+
+
+void Intrinsifier::Bigint_rsh(Assembler* assembler) {
+  // TODO(regis): Implement.
+}
+
+
 void Intrinsifier::Bigint_absAdd(Assembler* assembler) {
   // static void _absAdd(Uint32List digits, int used,
   //                     Uint32List a_digits, int a_used,
   //                     Uint32List r_digits)
 
   // R2 = used, R3 = digits
   __ ldp(R2, R3, Address(SP, 3 * kWordSize, Address::PairOffset));
   __ add(R2, R2, Operand(2));  // used > 0, Smi. R2 = used + 1, round up.
   __ add(R2, ZR, Operand(R2, ASR, 2));  // R2 = num of digit pairs to process.
   // R3 = &digits[0]
@@ skipping 1304 matching lines @@
   Isolate* isolate = Isolate::Current();
   __ LoadImmediate(R1, reinterpret_cast<uword>(isolate), kNoPP);
   // Set return value to Isolate::current_tag_.
   __ ldr(R0, Address(R1, Isolate::current_tag_offset()));
   __ ret();
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM64